力传感器进回程数据分布特点分析

Analytical Research on Reversibility Properties of Dynamometers

针对力值测量中进回程分布对不确定度的影响进行研究。在实际测量中,尽管在ISO376中定义了1.732这一包含因子,但力传感器的进回程分布并非是已知常见的分布,因此无法根据分布性质确定包含因子k。为了探究力传感器进回程特性,将采用包含因子的原始计算定义式对其进行计算分析。通过对严格控制实验条件得到的进、回程测量值,采用离散、连续两种分析方法,讨论进回程差实际分布特征,进而计算进回程差的包含区间,并最终确定包含因子k。通过核密度估计近似模拟,将离散型随机变量转变为连续型随机变量,得到未知分布的概率密度函数,并使用中心法以及最短包含区间进行分类讨论,最终获得95%与99%置信区间内的包含因子分别为1.846 3与2.221 6。

This paper presents the influence of reversibility on uncertainty of force measurements. In actual measurement,the coverage factor k of reversibility cannot be determined because of its unknown distribution, despite of the value of 1.732 defined in ISO376. The reversibility properties of force sensors are studied based on the definition of coverage factor. Using both discrete and continuous analyses, the actual distribution of reversibility are discussed and finally the coverage factor k is determined. The discrete random variable is transformed into a continuous one by estimating the kernel density. Then the probability density of the unknown distribution is simulated using the center method and the shortest coverage interval. The finally determined coverage factors corresponding to confidence intervals of 95% and 99% are 1.846 3 and 2.221 6,respectively.